It is common that connections such as telephone calls between calling and called lines be made by sharing a single communications path on a time division basis. Each call is assigned to a shared path for a short time interval and the connection between the two lines is completed only during the short time interval, also called a time slot in the TDM art. Otherwise, the time slot is available to be shared by other connections.
U.S. Pat. No. 3,263,030; entitled, "Digital Cross Point Switch" and issued July 26, 1966; discloses an arrangement for switching message bits from a first input time slot to a second output time slot. The arrangement includes two shift register message stores, which are utilized for writing digital data into one store while digital data are read out of the other store, and vice versa. The stored message bits are read through message gates in such a manner that the time sequence of the outgoing message bits represents the desired switched order. That is, the time sequence of the incoming multiplexed message bits is interchanged into a different output order. The order of the outgoing message bits corresponds to the outgoing lines to which the respective bits are to be routed. The routing is accomplished by actuating, successively and in time sequence, line gates respectively associated with the outgoing lines.
Unfortunately, known time slot interchange arrangements insert an input sample in a single output time slot.